INFLUENCE OF MYOCARDIAL TISSUE DOPPLER ON THE
ACCURACY OF DOBUTAMINE ECHOCARDIOGRAPHY IN NOVICES AND EXPERTS. RB. Fathi*, P. Cain, V. Khouri, T. Marwick. Princess Alexandra Hospital, University of
Queensland, Brisbane, Australia. Background: The interpretation of dobutamine
echocardiography (DbE) is currently based on qualitative wall motion scoring
(WMS) and has an important learning curve. Measurement of myocardial Doppler
velocity (MDV) using tissue Doppler may facilitate DbE interpretation and alter
the learning period. We assessed the influence of MDV on novice and expert
readers. Methods: Eighty-eight patients underwent
standard DbE and coronary angiography. Resting, low-dose (10mg/kg/min
dobutamine) and high-dose (40mg/kg/min dobutamine) images were
acquired in digital format. Images were analyzed by four independent observers
(two novices, two experienced); new or worsening wall motion abnormalities were
identified as ischemia and resting abnormality as scar. The WMS accuracy of
each reader was obtained by comparing segmental scoring to quantitative
angiography. MDV of all segments were measured independently and previously
derived cut-offs were applied to designate segments as normal or abnormal and
two strategies were used to integrate MDV. First, MDV data was used to identify
the diagnosis in every segment identified as negative by WMS. Second, MDV was
only applied to the six basal segments, as novice readers tend to demonstrate
low sensitivities in this region. Results: Sixty-seven pts had CAD. The
accuracy of the experienced readers exceeded that of novice readers (0.90 vs.
0.69, p<0.0001), as did sensitivity (0.98 vs. 0.71, p<0.0001). The
segmental concordance of novices with experts varied from Kappa of 0.417 to 0.706 (apical segments); 0.206 to 0.577 (mid segments);
and 0.087 to 0.78 (basal segments). The accuracy of WMS by novice readers was
improved by combination with MDV. Novice A's WMS accuracy improved from 70% to
74% with MDV and 77% when MDV was applied only basal segments. Novice B's
accuracy improved from 66% to 74% with MDV and 75% when MDV was restricted to
basal segments. This improvement was most marked when MDV application was
limited to the basal segments. With experienced echocardiographers however no
statistically significant change was noted. WMS
accuracy WMS
with MDV MDV
Basal only Novice
readers 69% 74%
(p=0.19) 77%
(p=0.03) Expert
readers 90% 86%
(p=0.07) 88%
(p=0.38) p
value <0.0001 <0.0001 <0.0001 Conclusion:
MDV improves the accuracy of less experienced readers but not the experienced
stress echocardiographer.
